1. Field of the Invention
The present invention generally relates to a flat panel display, more particularly to a flat panel display with a uniformly enhanced brightness and free of lamp mura.
2. Description of Related Art
With the high technology developing, video products, especially digital video or imaging devices, have become more popular in our life. For these video products, displays are the vital components for delivering associated image or information. Users may read information via the displays or further control the operation of the devices by the displays.
Most noticeable displays, such as direct backlight Liquid Crystal Displays (LCD), are developed by the combination of the optoelectronic technology and the semiconductor technology. Since the direct backlight LCDs have several advantage features such as low voltage operation, radiation free, light weight and compact in size, they recently become a main research subject, especially for the large size LCD TV.
FIG. 1 is a cross sectional view of a conventional direct backlight LCD. Referring to FIG. 1, the direct backlight LCD consists of a direct backlight module 100 and a liquid crystal display panel 110 as the image medium. Besides, the direct backlight module 100 comprises a plurality of lamps 102, a brightness enhancement film 140, a first diffuser plate 130, and a second diffuser plate 120. Lamp mura is referred to the observation of the lamps 102 shape, for example, a multi-stripe pattern for cold cathode fluorescent lamps (CCFL), on the liquid crystal display panel 110, which in turn deteriorates the quality of the images. Therefore, to avoid the lamp mura appearance over the lamps 102, the second diffuser plate 120 for diffusing light emitting from the lamps 102 is usually disposed between the backlight module 100 and the display panel 110. Typically, the second diffuser plate 120 with a higher haze value and a lower total transmittance is selected. However, such the above configuration will result in reducing the brightness, which in turn additionally necessitates the brightness enhancement film 140 for enhancing brightness. Furthermore, the first diffuser plate 130 is required to be added on the second diffuser plate 120 to avoid directly observing the shape of the lamps 102 if the second diffuser plate 120 with higher transmittance is employed.
The conventional LCD backlight module 100 has several drawbacks, such as poor brightness, bulky volume, long assembling time and poorly free of lamp mura. Accordingly, to overcome the preceding problems, a novel LCD backlight module is needed to promote its competence in the display market.